1. Field of the Invention
The present invention relates to a color thermal recording method and a color thermal printer. More particularly, the present invention relates to a color thermal recording method and a color thermal printer in which optical fixation of images can be regularly applied.
2. Description Related to the Prior Art
In a color thermal printer, a color thermosensitive recording material or sheet is used, to record a full-color image thereon according to the method of the frame-sequential printing. The recording material consists of a support and a cyan thermosensitive coloring layer, a magenta thermosensitive coloring layer and a yellow thermosensitive coloring layer, which are formed on the support in the order listed. Among those layers, the yellow coloring layer has the highest thermal sensitivity. The cyan coloring layer has the lowest thermal sensitivity. The yellow coloring layer has such a characteristic that its coloring ability is destroyed by application of near-ultraviolet rays of 420 nm. The yellow coloring layer is fixed before the magenta recording. The magenta coloring layer has such a characteristic that its coloring ability is destroyed by application of ultraviolet rays of 365 nm. The magenta coloring layer is fixed before the cyan recording.
Fixer lamps for emanating such ultraviolet rays have a cylindrical long shape, and are disposed crosswise to a direction of conveying the recording material. The recording material is kept flat while conveyed past a ray applying region defined under the fixer lamps. The ray applying region has a non-uniformity in the irradiance distribution of ultraviolet rays with respect to the conveying direction of the recording material, because of a difference between the cylindrical shape of the fixer lamps and the flatness of the recording material. To keep uniform a light amount of the ultraviolet rays between all points included in a recording area on the recording material, it is conceived that all the recording area is moved to a downstream end of the ray applying region of the fixer lamps. However it is inevitable that a small front portion of a non-recording area next to the recording area is moved into the ray applying region and subjected to ultraviolet rays. The small portion of the non-recording area is fixed before thermal recording being intended properly. If there is a partial image which should be recorded to the small portion, the partial image will not be recorded with a properly reproduced color. Accordingly a problem remains in that there occurs a portion of the recording material not usable effectively.